J. Nannoplankton Res., 38(1), 2020, pp. 57–79 © 2020 International Nannoplankton Association
ISSN 1210-8049 Printed by The Sheridan Press, USA

57

Middle Eocene to Early Oligocene calcareous nannofossils
from the Nanggulan Formation, Java, Indonesia
Amy P. Jones, Tom Dunkley Jones

School of Geography, Earth and Environmental Science, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; APJ527@student.
bham.ac.uk, t.dunkleyjones@bham.ac.uk
Manuscript received 15th May, 2019; revised manuscript accepted 28th June, 2020

Abstract In this article, we document the late Middle Eocene to Early Oligocene calcareous nannofossil assemblages from a new low-latitude site in the south-central region of Java, Indonesia. The studied assemblages arefrom the Nanggulan Formation, recovered from cores drilled in the Special Region of Yogyakarta. The study focusedon a ~60-m succession of marine clays and claystones that were recovered from Corehole NKK1, which includes anear-continuous Eocene–Oligocene section. The Late Eocene palaeolocation of this site was close to the region of themodelled peak sea-surface temperatures of the Eocene Indo-Pacific Warm Pool. Documenting coccolithophore communities from the tropical ocean through an interval of global cooling is important for several reasons. In particular,
the Late Eocene to Early Oligocene coccolithophore assemblages of NKK1 include species that are usually only
found in younger Oligocene assemblages, suggesting that this region may have been a key location for coccolithophore speciation and a source of increased diversity. Conversely, there were no significant range extensions of Lower
or Middle Eocene taxa up-section, suggesting a degree of synchrony in extinctions across the tropical to subtropicaloceans. A total of 115 species are documented, and two new species––Coccolithus aspida and Reticulofenestra nanggulanensis––are described.
Keywords Eocene, Oligocene, Java, taxonomy, calcareous nannofossils, biostratigraphy
1. Introduction
Calcareous nannofossils were examined from sedimentcores that were recovered in 2006 from the Middle Eocene
to Lower Oligocene portion of the Nanggulan Formation of Java. The cores were taken from drill-site NKK1,
near the village of Nanggulan, in the Special Region of
Yogyakarta (-7.788555˚S, 110.20578˚E; Figure 1). A fulldescription of the drilling operations, sedimentology andintegrated biostratigraphy is ongoing (Coxall et al., unpublished data, 2019). Sediments from these cores containabundant and well-preserved calcareous nannofossils. The
sedimentary sequences in NKK1 span the upper Middle
Eocene to Lower Oligocene, including a continuous record of the Eocene–Oligocene Transition (EOT), and canbe used to generate new records of tropical nannoplankton ecology and biostratigraphy through this critical interval of Earth history. Today, Java is located within the
Indo-Pacific Warm Pool (IPWP), which extends from thewestern waters of the equatorial Pacific Ocean, throughthe Indo-Australian Archipelago (IAA) and into the eastern Indian Ocean. The extent of the IPWP is defined byocean surface-waters with year-round temperatures exceeding 28˚C. In the modern climate system, these are thewarmest surface ocean-waters in the world (De Deckker,2016). In the Eocene, climate models have suggested that
the IPWP was both warmer and covered a larger regionof the Indo-Pacific Ocean than today (Huber & Caballero,
2011; Lunt et al., 2012). Palaeogeographic reconstructions(Hall, 2009, 2012, 2013) have placed NKK1 at the centreof this palaeo-IPWP during the Late Eocene. Today, the
IAA is the tropical centre of maximum diversity in marine
benthic communities (Renema et al., 2008).

Figure 1: Present day map of Eastern Asia, Indonesia and Australia, depicting the modern IPWP temperature gradients (orange) and the locationof core NKK1 in the southern region of Java

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Jones, Dunkley Jones

Fossil and molecular evidence indicate that these diversity hotspots have moved over the past ~50 Myr, inconjunction with major tectonic events (Renema et al.,2008). During the Eocene, neither Java nor the IAA wereareas of maximum invertebrate biodiversity (Renema etal., 2008). However, the Eocene equatorial Indian Ocean
region, including the East African margin, has recorded
higher species diversities than other, contemporary fossil
communities at similar tropical latitudes (Renema et al.,2008). For the plankton, and especially the calcareous phytoplankton, exceptionally-preserved Middle Eocene fossil
assemblages from the tropical East African margin record
peak species diversities (Bown et al., 2008). It is not clear
whether these high diversities are a product of exceptionalpreservation or reflect a primary biogeographic diversity
hotspot for calcareous phytoplankton in the tropical IndoPacific Ocean. The taxonomic assessment of calcareous
nannofossil assemblages from Java, close to the centre of
the palaeo-IPWP, help to address these questions of latitudinal and spatial diversity gradients of microplankton in
the Middle and Late Eocene.
During the Late Eocene to Early Oligocene, and especially across the EOT, there was a long-term decline in thediversity of calcareous phytoplankton species (Bown etal., 2004). High-resolution studies of this transition haveshown a gradual, progressive loss of species in the central(Fioroni et al., 2015) and eastern (Dunkley Jones et al.,2008) Indian Ocean. The current study, from the central
IPWP, has enabled the development of detailed assemblage and biostratigraphic records that test the nature of
species loss and extinction diachroneity across the tropicalIndo-Pacific. Here, we test the recently-proposed biostratigraphic zonation schemes developed for the mid-latitudes(Agnini et al., 2014) in a tropical low-latitude region close
to conditions of peak ocean warmth. The zonation of Agnini et al. (2014) included events based on the evolution
and extinction of species in the Reticulofenestra reticulata
group, in which there are subtle taxonomic discriminations across a group of morphologically-similar or intergrading species. We sought to test these species concepts
in Late Eocene ‘tropical endmember’ assemblages as away of assessing the recently-proposed bioevents, given
the known extinction diachroneity in this group (Berggren
et al., 1995; Villa et al., 2008; Persico et al., 2012).

2. Geological setting
During the Middle Eocene, Australia and Antarctica began
to separate as Australia migrated northwards. This placed
the Java region in a convergent tectonic regime that reinitiated Cretaceous subduction zones around the Sunda Arc,an active margin on the southerly side of Sundaland (Hall,
2009, 2012). Extensive islands and shallow seas were created (Hall, 2012, 2013) by subduction of the Australianand Pacific Plates below the continental part of Southeast
Asia (Hall, 2012). Southeast Asia increased in size throughthe addition of continental fragments that rifted away from
Australia and were subsequently added to the margins of
Sundaland (Hall, 2009). Palaeogeographic reconstructionsof Sundaland (the Malay Peninsula, Sumatra, Java, Borneo and surrounding small islands) during the Palaeogene
are subject to some uncertainty (Hall, 2013), but they indicate an Eocene palaeolatitude for NKK1 of ~-6.5˚S, which
is not dissimilar to the position of Java today (Hall, 2012;
Figure 1).
NKK1 was positioned to maximise the recovery of
the Middle Eocene to Oligocene sediments of the Nanggulan Formation that crops out northwest of the village ofKenteng, on the eastern flank of the Menoreh Hills. NKK1
penetrated a total depth of 100 m, and core recovery was>90% for most of the Watu Puru Beds and the Jetis Bedsof the Nanggulan Formation. Barren horizons or poorlypreserved nannofossil assemblages occurred in sediments
both immediately below and for an interval of ~3 m above
a basalt unit at ~40 m in the core. Nannofossil preservation
and recovery was more variable in the Lower to Middle
Oligocene upper Jetis Beds and Tegalsari Marls that occur
above the basalt horizon, and none of this material was
included in the current study. We focused on core samples
between 41.04 and 99.98 m below ground level (mbgl),
including samples NKK1-30 to NKK1-82, interpreted as
belonging to calcareous nannofossil Zones CNE15–CNO3of Agnini et al. (2014), equivalent to Zones NP17–NP23
of Martini (1971).
3. Sampling and methods
Sixty-five sediment samples were collected from NKK1
for calcareous nannofossil analysis. They were preparedusing the simple smear-slide technique of Bown & Young(1998). Specimens were observed using a Zeiss AxioScope in cross-polarised light (XPL) at x1250 magnification. Images were captured using QImaging and QCap-

Eocene–Oligocene nannofossils from Java

ture Pro 7 software. Calcareous nannofossil preservation
and abundances were determined for all samples using astandard semiquantitative scale, where abundance was A –abundant (>10–100 specimens per field of view [FOV]), C– common (>1–10 specimens per FOV), F – few (1 specimen per 1–10 FOV), and preservation was G – excellent/good (little/no dissolution and/or recrystallisation, primarymorphological characteristics slightly altered, specimens
identifiable to species level), M – moderate (minimaletching and/or recrystallisation, primary morphologicalcharacteristics somewhat altered, most specimens identifiable to species level), P – poor (badly etched/overgrown,
primary morphological characteristics mostly destroyed,with fragmentation and specimens not identifiable to species/genus level).
Nannofossil assemblage composition data for
NKK1 from the Middle Eocene to Lower Oligocene
can be found on figshare (https://doi.org/10.6084/
m9.figshare.12488783.v1) in the form of a range-chart for
all samples studied. At least 400 specimens were counted
from each sample, followed by an additional scan of atleast two transects of each slide, in order to maximise theidentification of rare species. Any species noted outside of
the count are represented by an asterisk (*) in the chart.
4. Biostratigraphy
The biostratigraphic interpretation of the NKK1 samples(Figure 2) employed the calibrated bioevents of Agnini etal. (2014); both the Agnini et al. (2014) and Martini (1971)
biozonation schemes are shown for reference in Table 1.
All ages were adjusted to the Geologic Timescale 2012
(Gradstein et al., 2012). Establishing robust bioevents forbiozonation schemes for the Late Eocene has been difficult. Of those bioevents proposed by Martini (1971), thebases of Sphenolithus pseudoradians and Isthmolithus recurvus are diachronous across latitudes, and I. recurvus isentirely absent from tropical environments (Wei & Wise,
1990; Dunkley Jones et al., 2008, 2009; Fioroni et al.,2015). Agnini et al. (2014) sought to remedy this lack ofreliable bioevents with the addition of a series of events
based on the R. (Cribrocentrum) reticulata lineage. The
successive appearances and extinctions of these typicallytropical to subtropical species through the Late Eocene has
the potential to significantly improve low- to mid-latitude
nannofossil biozonations. However, one possible complicating factor involves the morphotypes in the R. reticulata

59

lineage. Fornaciari et al. (2010) defined two new species––
Cribrocentrum (Reticulofenestra) isabellae for large (>12µm) forms with narrow central-areas and C. erbae with abroad tube and distinctly closed central-area. Agnini et al.
(2014) used both species as biohorizon marker taxa, but it
is not clear how their revised taxonomy relates to previous
biostratigraphic studies that did not make any distinction
between the morphotypes of R. reticulata. Here, we carefully examined the variability in the R. reticulata lineage,
with the purpose of refining the existing taxonomy of its
morphotypes and documenting the range of these morphotypes through the late Middle to Late Eocene in a tropicallocation.
The studied samples encompassed CNE15–CNO3 andNP17–NP23 (Bartonian–Rupelian), an interval that included the Eocene–Oligocene boundary (E/OB). CNE17–
18 and NP18 were missing between 88.02 and 86.85 mbgl
due to an unconformity at the contact between the upper
Watu Puru Beds and lower Jetis Beds. The Watu Puru
Beds (100–88.02 mbgl, totalling 11.98 m) are Bartonianin age, spanning CNE15 (NP16–NP17), and consist of
thinly-bedded, silty claystones, interbedded with alternating tuffaceous, andesitic sandstones. The nannofossil preservation varied from moderate in samples with a higher
sand content to good in silty clay samples. The Jetis Beds
represented the majority of the material examined, ranging from 86.85–41.04 mbgl (totalling 45.81 m), and dated
as CNE19 (NP19/20, Priabonian) at the base. All samples
comprised silty clays and mudstones, varying from dark
to light olive-greens and greys. Between 75.75 and 69.60
mbgl, there was a reddish-brown interval with greenishgrey spots that contained the core’s best-preserved nannofossil specimens.
5. Taxonomic discussion
Two species (Sphenolithus conicus and Triquetrorhabdulus carinatus), which typically appear in the mid- to Late
Oligocene (de Kaenel & Villa, 1996; Blaj et al., 2009;
Bergen et al., 2017), were identified in the Middle to Upper Eocene sediments of NKK1. This does not appear to
be a function of preservation, as both of these species areabsent from other Upper Eocene assemblages that haveexcellent preservation, such as the Tanzanian successions
and IODP Expedition 342 in the the North Atlantic Ocean(Bown, 2005; Dunkley Jones et al. 2008, 2009; Bown &Newsam, 2017).

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Jones, Dunkley Jones

nannofossil
plankt. foram

Figure 2: Age/depth plot for NKK1, showing the nannofossil bioevents from Table 1, modified after Jones et al. (2019). Scale and biozones after
Agnini et al. (2014). Ages adjusted to the GTS2012 (Gradstein et al., 2012)

Table 1: Comparative biostratigraphy of NKK1, using the Agnini et al. (2014) and Martini (1971) biozonation schemes

Sphenolithus conicus is a common mid- to Upper Oligocene species in many pelagic successions (Blaj et al.,2009; Bown & Dunkley Jones, 2012; Bergen et al., 2017).
In NKK1, however, S. conicus morphotypes appearedin the latest Eocene (Sample NKK1-54a, CNE19, ~35.1
Ma), typically with low abundances that increased into theLower Oligocene. The S. conicus morphotype observed in
NKK1 is smaller than the specimens originally describedby Bukry (1971), although Bown & Dunkley Jones (2012)
also documented a small morphotype in sediments from
CNE21 (NP21) from IODP Expedition 320 in the equatorial Pacific. In NKK1, these small S. conicus morphotypes are consistently present in assemblages interpreted
as CNE19 (NP19/20) (72.44 mbgl, ~35.18 Ma). These
specimens are the smallest at the base of their observed

range (latest Eocene), increasing in size into the Oligocene(Table 2). Sphenolithus conicus first appeared in the IPWP,
only later appearing in the East Pacific, suggesting that, in
the Early Oligocene, this species was limited to the tropical Pacific.
Triquetrorhabdulus carinatus, a nannolith with uncertain taxonomic affinities, was also present, albeit rarely
and sporadically, in CNE19 to CNO3 (NP19/20–NP23,~35.9 –~31.2 Ma) in the Jetis Beds, although it occurred
frequently in Sample NKK1-48a (64.55 mbgl, ~34.7 Ma).
Young (1998) and Agnini et al. (2014) stated that the baseof T. carinatus is in CNO5 (NP25). In our section, it was
first observed in CNE19 (NP19/20), approximately 7–8
Myr earlier. Lower Middle Eocene occurrences of T. carinatus have been reported from ODP Sites 1209, 1210 andEocene–Oligocene nannofossils from Java

61

Table 2: Measurements of R. nanggulanensis and S. conicus in NKK1

1211, Shatsky Rise, NW Pacific Ocean (Bralower, 2005).
Its reported abundances varied from rare to abundant,
but there are no figures to accompany these data, and its
identification may have been uncertain. There are multiple occurrences of this morphotype in NKK1, in several
samples, suggesting that early forms of T. carinatus first
appeared in the Late Eocene in tropical locations.
Circular reticulofenestrid coccoliths, with distinct
central-area nets, are key Middle to Late Eocene taxa,
with R. isabellae and R. reticulata being stratigraphicallyimportant (Agnini et al., 2014). They are also palaeoenvironmental markers of relatively warm-water conditions(Bukry, 1973; Aubry, 1992a, b; Newsam et al., 2017).
Some authors have placed these forms in the genus Cribrocentrum (Fornaciari et al., 2010; Shamrock & Watkins,
2012; Agnini et al., 2014; Self-Trail et al., 2019), but wehave retained their placement in the genus Reticulofenestra, whilst recognising the same species-level distinctions
that are in use. Reticulofenestra isabellae was describedby Fornaciari et al. (2010) as having large (>12 µm), circular placoliths with a central-area net. These morphotypes
are effectively a large variant of Reticulofenestra reticulata, which includes medium to large (6–12 µm) coccoliths
with a small central-area and distinctive extinction patternof two crossed ‘dumbbells’ in the light microscope (LM)
(Perch-Nielsen, 1985). Reticulofenestra erbae is similar to
R. reticulata, but has a broad tube and closed central-area(Fornaciari et al., 2010). This morphotype was not seen in
NKK1, as its stratigraphic range falls within the unconformity between the Watu Puru and Jetis Beds.
The top of R. reticulata is known to be diachronous across latitudes (Berggren et al., 1995), occurring at~35.32 Ma in the northern mid-latitudes (Agnini et al.,2014), between 36.30 and 36.69 Ma in the southern highlatitudes (Villa et al., 2008; Persico et al., 2012) and with a

top common occurrence (TCO) at ~34.99 Ma at equatorial
Indian Ocean ODP Site 711 (Fioroni et al., 2015). According to Fornaciari et al. (2010), the top of R. isabellae iscoincident with the top of R. reticulata at 35.21 Ma in the
Massignano, Zermagnone and Bottaccione sections. Thisfinding is supported by the NKK1 biostratigraphy, where
the top of R. isabellae coincides with the top of R. reticulata at 61.57 mbgl. However, based on the age model for
NKK1 (Figure 2), we estimate the synchronous extinctions of R. reticulata and R. isabellae to be at ~34.5 Ma(CNE20; Figure 3), which is ~0.7–0.8 Myr younger thanreported for the northern low to mid-latitudes (Fornaciari
et al., 2010; Agnini et al., 2014). Several other Late Eocene tropical nannoplankton have also shown a pattern ofcontinued existence in tropical environments, while being
absent from more northerly and southerly regions (Berggren et al., 1995; Dunkley Jones et al., 2008; Fioroni etal., 2015). The co-extinction of these two morphotypes in
NKK1 and at other locations (Fornaciari et al., 2010) poses the question whether separating the two species, basedon a 12 µm size difference, is an arbitrary division of a
population with continuous size variability. However, thelimited age range of the large morphotype may still havebiostratigraphic utility in the Upper Eocene (Agnini et al.,2014).
Reticulofenestra nanggulanensis sp. nov. is distinguished from R. reticulata by its characteristically wide
central-area, and from R. lockeri by its subcircular shape(Plate 1, figs 40–42). Reticulofenestra nanggulanensis ismedium in size (5–7 µm), with a single, slim outer cycle,
and lacks the inner cycle that is present in R. reticulata andR. isabellae. This morphotype has been illustrated previously by Bown & Newsam (2017; Plate 2, figs 7–9) as R.
reticulata (wide). This new species is not only distinct, butalso has a different stratigraphic range from R. reticulata.

62

Jones, Dunkley Jones

Fornaciara
et al. (2010)

Agniniet al. (2014)

Fioriniet al. (2015)

Villa
et al. (2008)

Persicoet al. (2012)

Middle

17

Late

top

base

Figure 3: Stratigraphic distribution of R. reticulata and R. isabellae, showing diachroneity in the occurrences of these species across different latitudes. The northern, low- to mid-latitude data are from IODP Site 1218, ODP Sites 1051 and 1052, the Cicogna and Possagno sections and the Mediterranean area (Fornaciari et al., 2010; Agnini et al., 2014). The equatorial low-latitude data are from NKK1 (this study) and ODP Site 711 (Fioroni
et al., 2015). DSDP Site 522 and IODP Site 1262 give the southern mid-latitude data (Fornaciari et al., 2010; Agnini et al., 2014). The southern highlatitude data are from ODP Holes 784B (Villa et al., 2008) and 689D (Persico et al., 2012). Ages for the occurrences of R. reticulata and R. isabellae
have been recalibrated against the GTS2012 (Gradstein et al., 2012)

It occurs in stratigraphically older sediments, in CNE15(NP16/17, 99.98–88.86 mbgl), and with rare abundances
above the extinction of R. reticulata, up to CNO1 (NP21,
46.21 mbgl) in the Lower Oligocene. Once R. reticulata
appears in the section (88.86 mbgl), the abundance of R.
nanggulanensis decreases, although it occurs consistently
in all samples up to the end of CNE19 (NP19/20, 64.55
mbgl), and then continues as rare occurrences into thelowest Oligocene.
The recognition of species of Calcidiscus throughout
the Palaeogene is growing (Bown et al., 2007; Dunkley
Jones et al., 2009; Bown & Dunkley Jones, 2012; daGama & Varol, 2014). Calcidiscids are present, although
not particularly diverse, in NKK1, but two species wererecognised––C. bicircus and C. cf. C. gallagheri (Plate 3,
figs 9–11, Plate 3, figs 14–17). It is possible that additional

species are present in the oldest section of the core, but
the poor preservation of central-area structures in thesesamples makes this equivocal. From DSDP Leg 25 Site
242 in the western Indian Ocean, along the Davis Ridge,
da Gama & Varol (2014) described one new species––C.
gallagheri––from CNO5 (NP25). We recorded the occurrence of a specimen similar to C. gallagheri in the Upper
Eocene. The base of C. cf. C. gallagheri in the NKK1 core
was found in CNE19 (NP19/20), above which, this species became progressively more common into the lowest
Oligocene (64.55–41.04 mbgl).
A new species of Coccolithus––C. aspida (Plate 2, figs
1, 2)––is described from NKK1. The morphological variation in the genus Coccolithus in the NKK1 assemblages
was high, in terms of both size and central-area structure.
Closely-coupled genetic and morphological variation inEocene–Oligocene nannofossils from Java

modern Coccolithus species (Narciso et al., 2006) supports a robust differentiation among species based on
subtle morphological differences. Coccolithus aspida isclearly distinct from C. pelagicus due to its closed centralarea and broad outer rim, and it is persistently common
throughout NKK1. Coccolithus pelagicus and its morphotypes all have an open central-area, some spanned by bars
and crosses, but this is the first species to be described witha fully-closed central-area.
Overall, application of the Agnini et al. (2014) biozonation scheme to the NKK1 data worked well, whilst using both Agnini et al. (2014) and Martini (1971) improves
the stratigraphic subdivision of the Upper Eocene, withmore nannofossil biohorizons being identified at low- andlow-mid-latitude locations. The calibrated ages of Late
Eocene bioevents from Agnini et al. (2014) provided acoherent age model for NKK1, and are highly consistent
with the bioevent ages from planktonic foraminifera. The
only problematic datum was the top of R. reticulata, which
was offset from the general age-depth trend defined by thenannofossil and planktonic foraminiferal age constraints(Figure 2). Based on the age model for NKK1, we estimatethat the top of R. reticulata was ~0.7–0.8 Myr younger in
NKK1 than was estimated by Agnini et al. (2014), supporting previous indications for latitudinal diachroneity ofthis event (Berggren et al., 1995). The Middle and Middle–Upper Eocene biostratigraphy of NKK1 was complicatedby the unconformity between the upper Watu Puru Beds
and lower Jetis Beds (88.02–86.85 mbgl), which spanned
CNE17–CNE18 and NP18. As a result, the boundary between the Middle and Upper Eocene was not present in thesection, and it was thus not possible to assess the applicability of these zones in this study.
6. Systematic palaeontology
Images of some of the nannofossils found in NKK1 arepresented in six plates. These plates display the diversity
and morphological variation of species recorded from theupper Middle Eocene to Lower Oligocene. The descriptive terminology below follows Young et al. (1997), andthe higher taxonomic classification is based on Young &Bown (1997) for extinct taxa and Young et al. (2003) for
extant taxa. We aimed to make the taxonomy consistent
with recent, extensive systematic studies of Palaeogene
calcareous nannofossils (Bown, 2005; Bown et al., 2007;
Dunkley Jones et al., 2009; Bown & Dunkley Jones, 2012;63

Bown & Newsam, 2017). Our taxonomic comments only
pertain to taxa with particular significance, species where
our taxonomic concepts diverge from, or are a clarificationof, those previously published, or are descriptions of thetwo new species.
The sample identifications on the plates use a ‘core,section (A or B) and interval-in-section (cm)’ notation.
Where an image is a rotation of the same specimen as thepreceding image, the sample information is not replicated.
Additionally, the name of a specimen is not replicatedwhen it is of the same species. All images were taken at
the same magnification.
6.1 Placolith coccoliths
Order ISOCHRYSIDALES Paascher, 1910
Family NOELAERHABDACEAE Jerkovic, 1970
emend. Young & Bown, 1997
Cyclicargolithus ﬂoridanus group
Pl. 1, figs 8–10
Description: Small to large, subcircular to broadly elliptical reticulofenestrids displaying a narrow central-area andindiscernible net (which may be missing or non-birefringent).
Cyclicargolithus ﬂoridanus (Roth & Hay in Hay et al.,1967) Bukry, 1971
Pl. 1, figs 9, 10
Remarks: All small to large (3–11 µm), subcircular reticulofenestrids possessing a narrow central-area. Specimens with a closed central-area were here placed in C. cf.
C. ﬂoridanus.
Cyclicargolithus cf. C. ﬂoridanus (Roth & Hay in Hay etal., 1967) Bukry, 1971
Pl. 1, fig. 8
Remarks: C. ﬂoridanus with a closed central-area.
Reticulofenestra bisecta group
Pl. 1, figs 20, 21, 31–34
Description: Reticulofenestras (Dictyococcites of someauthors) with a central-area that is birefringent, and64

Jones, Dunkley Jones

Plate 1

Reticulo. minuta 73A-30

82A-97 R. dictyoda

81A-46

70A-5

82A-97

62A-14

R. dictyoda

81A-46 C. cf. C. ﬂoridanus 82A-97 Cycli. ﬂoridanus 31A-40

35B-109 R. wadeae

R. lockeri

79A-42

79A-42

65A-84

73A-30 R. cf. R. lockeri 60A-60 R. macmillanii 78A-39

R. macmillanii

34B-49 R. filewiczii

34B-4959C-80 R. daviesii

31A-40R. westerholdii

82A-97

81A-46 Ret. protococcolith 30B-106

31A-40 R. reticulata (circ.) 64A-23

55A-23

R. bisecta

73A-30

31A-40 R. stavensis

34B-124 R. umbilicus

56A-1947A-63

73A-3074A-74

31A-40

31A-40R. nanggulanensis 82A-97
R. cf. R. reticulata 58B-78 R. reticulata

R. reticulata

74A-74

65A-84

65A-84

65A-84 R. isabellae

61B-119

82A-97 Ret. coccosphere 63A-23

55A-53

38A-44

65A-84Eocene–Oligocene nannofossils from Java65

closed by a distinct plug. Included species: R. bisecta (D.
scrippsiae), R. filewiczii, R. stavensis (D. bisectus).

Reticulofenestra cf. R. lockeri Müller, 1970
Pl. 1, fig. 17

Reticulofenestra bisecta (Hay et al., 1966) Roth, 1970
Pl. 1, figs 31, 32

Remarks: Similar to R. lockeri, but with a wider centralarea that has a visible (birefringent) net.

Remarks: Elliptical and medium to large (less than 10 µmlong), with a solid plug.

Reticulofenestra macmillanii Dunkley Jones et al., 2009
Pl. 1, figs 18, 19

Reticulofenestra filewiczii (Wise & Wiegand in Wise,
1983) Dunkley Jones et al., 2009
Pl. 1, figs 20, 21

Remarks: Similar to R. lockeri, but smaller, and with awider central-area.

Remarks: Differs from the rest of the group in having asmall central opening and weakly birefringent net.
Reticulofenestra stavensis (Levin & Joerger, 1967)
Varol, 1989
Pl. 1, figs 33, 34
Remarks: Similar morphology to R. bisecta, but distinguished by its larger size (>10 µm).
Reticulofenestra lockeri group
Pl. 1, figs 13–19, 22–24
Description: Elliptical reticulofenestrids with a visible(birefringent) net, with perforations that are sometimes
discernible in the LM. Included species: R. daviesii, R.
lockeri, R. cf. R. lockeri, R. macmillanii.
Reticulofenestra daviesii (Haq, 1968) Haq, 1971
Pl. 1, figs 22–24
Remarks: Differentiated from R. lockeri by the single rowof perforations on each side of the netted central-area. The
species became more common above the E/OB, but wassporadic throughout the section.
Reticulofenestra lockeri Müller, 1970
Pl. 1, figs 13–16
Remarks: Elliptical, with a visible central-area net thathas no perforations observable in the LM. The central-area
is narrow; those with wider central-areas were placed in R.
cf. R. lockeri.

Reticulofenestra reticulata group
Pl. 1, figs 25, 26, 37–47
Description: Medium to very large, circular reticulofenestrids with a circular to broadly-elliptical central-area,spanned by a robust and conspicuous (birefringent) net.
Included species: R. isabellae, R. nanggulanensis, R. reticulata, R. cf. R. reticulata, R. westerholdii.
Reticulofenestra isabellae (Catanzariti et al. in Fornaciari
et al., 2010) Bown & Newsam, 2017
Pl. 1, figs 45–47
Remarks: Very large reticulofenestrid (>12 µm), with arelatively narrow central-area and broad tube-cycle. Occurrence: CNE16–CNE20, NP17–NP19/20.
Reticulofenestra nanggulanensis sp. nov.
Pl. 1, figs 40–42
Derivation of name: After the Nanggulan Formation insouth-central Java, the geological formation from which
the NKK1 samples originated. Diagnosis: Small to medium, subcircular reticulofenestrid, with a distinct, wide
central-area (>1.5 times the rim width). The central-areais spanned by a visible (birefringent) net. Differentiation:
Similar to R. reticulata, but has only one outer shield anda distinctly wider central-area, which varies from broadly elliptical to subcircular. Remarks: Most common in
CNE15 (NP17), and more common than other members of
the R. reticulata group in this core. Consistently observed
up to the top of CNE19 (NP19/20), and present to the topof CNO1 (NP21). Dimensions: Holotype length = 6.0µm; paratype length = 7.2 µm. Holotype: Plate 1, fig. 40.

66

Jones, Dunkley Jones

Plate 2

Cocco. aspida 82A-97

73A-30 C. pelagicus

C. hulliae?

56A-1981A-46

C. cachaoi

73A-3033A-43

31A-4082A-97

81A-46 C. scheri 46B-111

59B-110 Coccolithus sp.

Bram. serraculoides 41A-70

77A-1356A-1973A-3045A-4833B-120 C. cruciformis

C. nitidus

C. eopelagicus

82A-97

41A-70 C. eopelagicus

66A-51

30A-53

77A-13 C. biparteoperculatus 47A-55

C. biparteoperc.? 48A-54 C. cf. C. biparteoperculatus

C. tarquinius

82A-97

73A-30 C. formosus

82A-9758B-93 Cruci. primus

59B-110

77A-13

49A-25 Campylo. dela

74A-74

80A-73 C. nitescens

59B-110

81A-46

74A-74 C. titus

81A-4659B-110

Chiasmo. nitidus 45A-48

C. titus

78A-39 C. eoaltus

82A-97 C. grandis

80A-7380A-73

Eocene–Oligocene nannofossils from Java

Paratype: Plate 1, fig. 41. Type locality: NKK1, Nanggulan, Java. Type level: Upper Middle Eocene, NKK1-82A97cm, CNE15, NP17. Occurrence: Recorded in upper
Middle Eocene to Lower Oligocene sediments, CNE15–
CNO1, NP16–NP17. Top recorded in sample NKK1-33b(46.21 mbgl).
Reticulofenestra reticulata (Gartner & Smith, 1967)
Roth & Thierstein, 1972
Pl. 1, figs 38, 39, 43, 44
Remarks: Used broadly for medium to large (<12 µm),
circular reticulofenestrids, with a broad tube-cycle andnarrow central-area having a visible (birefringent) net.
Reticulofenestra cf. R. reticulata (Gartner & Smith, 1967)
Roth & Thierstein, 1972
Pl. 1, fig. 37
Remarks: Similar to R. reticulata, but with a larger central-area. This form has two distinct cycles and, therefore,
is not R. nanggulanensis.
Reticulofenestra reticulata (circular) (Gartner & Smith,1967) Roth & Thierstein, 1972
Pl. 1, figs 28–30
Remarks: Similar to R. reticulata, but circular rather thanhaving the common broadly-elliptical shape.
Reticulofenestra westerholdii Bown & Dunkley Jones,2012
Pl. 1, figs 25, 26
Remarks: Circular, with a central-area net that is not
visible in the LM. Morphologically very similar to othermembers of the R. reticulata group.
Reticulofenestra umbilicus group
Pl. 1, figs 1–7, 11, 35, 36
Description: Elliptical and subcircular reticulofenestrids
with an open central-area, spanned by a thin, faint (nonbirefringent or missing) net. Included species: R. dictyoda,
R. minuta, R. umbilicus, R. wadeae.

67

Reticulofenestra dictyoda (Deflandre in Deflandre & Fert,
1954) Stradner in Stradner & Edwards, 1968
Pl. 1, figs 3–7
Remarks: Used broadly to distinguish medium to large,
elliptical reticulofenestrids, with relatively-open centralareas.
Reticulofenestra minuta Roth, 1970
Pl. 1, figs 1, 2
Remarks: Used broadly here for elliptical reticulofenestrids that are very small (<3 µm).
Reticulofenestra umbilicus (Levin, 1965)
Martini & Ritzkowski, 1968
Pl. 1, figs 35, 36
Remarks: Very large (>14 µm), elliptical reticulofenestrid.
Reticulofenestra wadeae Bown, 2005
Pl. 1, fig. 11
Order COCCOLITHALES Haeckel, 1894
emend. Young & Bown, 1997
Family COCCOLITHACEAE Poche, 1913
emend. Young & Bown, 1997
Coccolithus pelagicus group
Pl. 2, figs 1–5, 11, 17, 21, 22
Description: Elliptical to subcircular Coccolithuses, witha central opening sometimes having a delicate bar or cross.
Coccolithus aspida sp. nov.
Pl. 2, figs 1, 2
Derivation of name: From the Greek ‘aspída’, meaning‘shield’, referring to the distinctive Coccolithus-type outerrim. Diagnosis: Medium to large, elliptical Coccolithus,
with a noticeable V-unit-dominated outer rim that is larger
than the tube-cycle and possesses an apparently-closed
central-area. Differentiation: Distinguished from C. pelagicus by its closed central-area. Remarks: This species
occurred commonly in all the samples from NKK1. Al-

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Jones, Dunkley Jones

Plate 3

Clausi. subdistichus76A-24

C. fenestratus

56A-1976A-24

61A-23 Calcidiscus bicircus

C. cf. C. bicircus 55A-53 C. cf. C. gallagheri 59B-110

U. detecta

74A-74

35A-55 C. fenestratus

60A-6064A-23

73A-30 C. cf. C. bicircus 55A-53

30A-5330A-53 Pedino. larvalis 61A-23

59B-110 U. edgar. 34B-124 U. jord. 59B-110 U. protoann. 54A-43 U. bramlettei 51A-42

Helico. euphratis 34B-124 H. bramlettei

82A-97 H. wilcoxonii

59B-110 H. reticulata

P. multipora

P. alta

82A-97 H. lophota

65A-84

59A-6746B-124 P. larvalis

31A-4076A-24 H. compacta

31A-4059B-110
H. reticulata

H. clarissima

30A-5330A-53 Pontosphaera exilis 63A-23

80A-73
P. exilis

74A-7459B-11080A-73 P. distincta

74A-74

61A-23 P. obliquipons

35A-55

63A-23

31A-40

61A-23

64A-2359B-110Eocene–Oligocene nannofossils from Javathough this species is characterised by a closed centralarea, its overall morphology and crystallography are very
similar to those of C. pelagicus, and so we have placed the
new species in Coccolithus, pending further observationsof this morphotype. In the future, the generic descriptionof Coccolithus (having an open central-area) may need tobe emended. Dimensions: Holotype length = 10.8 µm,
paratype length = 8.1 µm. Holotype: Plate 2, fig. 2. Paratype: Plate 2, fig. 1. Type locality: NKK1, Nanggulan,Java. Type level: Middle Eocene, Sample NKK1-73A30cm, CNE15, NP17. Occurrence: Recorded in Middle
Eocene to Lower Oligocene sediments, CNE15–CNO3,
NP16–NP23.

69

Coccolithus cf. C. biparteoperculatus
Pl. 2, figs 19, 20
Remarks: Similar to C. biparteoperculatus, but the bipartite, oval bar appears perforated, making it look like a net
or grill, which may be the result of overcalcification.
Coccolithus cachaoi Bown, 2005
Pl. 2, figs 12–14
Coccolithus scheri Bown & Dunkley Jones, 2012
Pl. 2, figs 9, 10
Other Coccolithus species

Coccolithus eopelagicus (Bramlette & Riedel, 1954)
Bramlette & Sullivan, 1961
Pl. 2, figs 11, 17

Coccolithus formosus (Kamptner, 1963) Wise, 1973
Pl. 2, fig. 23

Coccolithus sp.
Pl. 2, figs 21, 22

Coccolithus hulliae? Bown & Newsam, 2017
Pl. 2, figs 6–8

Description: Large and broadly elliptical Coccolithustype coccolith, with a broad rim and a delicate, disjunct,transverse bar that spans the open central-area and has asmall nodule in the centre. The bar curves slightly at eachend when the ellipse is aligned at 0˚. When rotated to 45˚,
the transverse bar becomes a thin, dark ‘S’-shape, similar
to that of Chiasmolithus titus, although C. titus is otherwise distinctly dissimilar. Remarks: Only one specimen
was recorded, in NKK1-73A-30cm, CNE15, NP16/17,
Middle Eocene.

Remarks: Questionable assignment because the centralarea cross is different from that described by Bown &Newsam (2017). As pictured in Plate 2, C. hulliae? has a
disjunct axial cross that intersects the inner cycle. However, the rim morphology is similar to that described by
Bown & Newsam (2017).

Coccolithus pelagicus (Wallich, 1877) Schiller, 1930
Pl. 2, figs 3–5
Coccolithus biparteoperculatus group
Pl. 2, figs 9, 10, 12–16, 18–20
Description: The central-area, which can be broad or netted, is filled by a bar.
Coccolithus biparteoperculatus (Varol, 1991)
Bown & Dunkley Jones, 2012
Pl. 2, figs 15, 16, 18

Chiasmolithus bidens group
Pl. 2, figs 43–45
Chiasmolithus eoaltus Persico & Villa, 2008
Pl. 2, fig. 43
Chiasmolithus grandis (Bramlette & Riedel, 1954)
Radomski, 1968
Pl. 2, figs 44, 45
Remarks: This species was recorded from the base of thecore, although its presence was rare. However, an acmeof C. grandis was observed in one sample (NKK-1/66,
51–52), just below the unconformity between 88.02 and86.85 mbgl.

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Jones, Dunkley Jones

Plate 4

48A-54 P. enormis

P. plana 61A-23

82A-97 P. latoculata

56A-19P. latoculata

30A-53

49A-25 B. gladius?

31A-4058B-93 B. stilus

43B-109 B. culter?

74A-74

66A-51

53A-2058B-93 B. spiculiformis 57A-38

58A-42

74A-74B. tenuis

B. spinosus 59B-110

67A-35 B. spinosus

30A-53

58A-42

B. spinosus

B. subtilis?

50A-47

61A-23

65A-84 Scypho. columella 48B-108 S. expansa

Blackites amplus 77A-13 B. cf. B. globosus 32B-120

B. tortilis

67A-35 P. formosa (small) 77A-13

63A-23

Pontosphaera duocava

P. pectinata

P. duocava

63A-2358B-93 B. inversus

65A-84 Calciosolenia alternans

30A-53

73A-3082A-97 Syracosphaera tanzanensis

63A-23

Eocene–Oligocene nannofossils from Java

Chiasmolithus consuetus group
Pl. 2, figs 36–42
Chiasmolithus nitidus Perch-Nielsen, 1971
Pl. 2, figs 36–39
Chiasmolithus titus Gartner, 1970
Pl. 2, figs 40–42
Campylosphaera–Cruciplacolithus group
Pl. 2, figs 24–34
Bramletteius serraculoides Gartner, 1969
Pl. 2, figs 24–27
Campylosphaera dela (Bramlette & Sullivan, 1961)
Hay & Mohler, 1967
Pl. 2, figs 33, 34
Cruciplacolithus cruciformis (Hay & Towe, 1962)
Roth, 1970
Pl. 2, figs 31, 32
Cruciplacolithus primus Perch-Nielsen, 1977
Pl. 2, figs 28, 29
Description: Small, elliptical Cruciplacolithus, with adisjunct, axial cross in the central-area. Very narrow, bicyclic rim.
Cruciplacolithus tarquinius Roth & Hay in Hay et al.,1967
Pl. 2, fig. 30
Description: Narrowly elliptical, and small to medium insize. The central-area contains a small, delicate axial cross.
The rim is bicyclic, and broader than that of C. primus.
Clausicoccus group
Clausicoccus fenestratus (Deflandre & Fert, 1954)
Prins, 1979
Pl. 3, figs 5–8
Clausicoccus subdistichus (Roth & Hay in Hay et al.,1967) Prins, 1979
Pl. 3, figs 1–4

71Coronocyclus group
Coronocyclus nitescens (Kamptner, 1963)
Bramlette & Wilcoxon, 1967
Pl. 2, fig. 35
Family CALCIDISCACEAE Young & Bown, 1997
Calcidiscus bicircus Bown, 2005
Pl. 3, figs 9–11
Calcidiscus cf. C. bicircus Bown, 2005
Pl. 3, figs 12, 13
Remarks: Similar to C. bicircus, but with a closed centralarea and visible (birefringent) net.
Calcidiscus cf. C. gallagheri da Gama & Varol, 2014
Pl. 3, figs 14–17
Description: Broadly elliptical, medium to very large.
The central-area is distinctive, with a delicate net (partially
missing in both specimens) and small perforations visible
in the LM. Remarks: The central-area is more irregularthan that described by da Gama & Varol (2014); this specimen appears to be more heavily calcified, despite being ofa similar size and shape.
Umbilicosphaera bramlettei (Hay & Towe, 1962)
Bown et al., 2007
Pl. 3, figs 23, 24
Remarks: A variation in size was documented in the Upper Eocene through Lower Oligocene of NKK1. Larger
specimens (>8 µm) occurred in the lower Upper Eocene(CNE19, NP19/20).
Umbilicosphaera detecta (de Kaenel & Villa, 1996)
Young & Bown, 2014
Pl. 3, fig. 19
Umbilicosphaera edgariae (Bown & Dunkley Jones,
2012) Young & Bown, 2014
Pl. 3, fig. 20
Umbilicosphaera jordanii Bown, 2005
Pl. 3, fig. 21

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Jones, Dunkley Jones

Plate 5Lanternithus minutus 77A-13

H. minoletti

62A-1434B-124

79A-42 Neochias. tenansa

31A-40 Holodisco. minolettii 70A-5

58B-9359B-11059B-110 Clathro. ellipticus 64A-23

Orthozygus aureus

Zygrhab. b. bijugatus 48B-108

41A-70B. bigelowii

Braarudosphaera bigelowii

59C-120

76A-24 Micran. astrum? 58B-93 Pem. basquense 56A-19

C. ellipticus

80A-73

82A-9764A-23

60A-60 P. papillatum

82A-97

63A-2356A-19 indet. nannolith

30A-5346B-124
Discoaster distinctus

D. distinctus

70A-5

59A-67

P. papill. 58B-93 P. triquetra

P. papillatum

31A-4046B-124

34B-124 D. septemradiatus?

79A-42 D. nodifer46B-124 D. tanii ornatus

63A-23

41A-7067A-35

82A-97 D. tanii

81A-46

Eocene–Oligocene nannofossils from Java

Umbilicosphaera protoannulus (Gartner, 1971)
Young & Bown, 2014
Pl. 3, fig. 22

Pontosphaera duocava (Bramlette & Sullivan, 1961)
Romein, 1979
Pl. 4, figs 1–4

Placolith coccoliths incertae sedis

Pontosphaera enormis (Locker, 1967)
Perch-Nielsen, 1984
Pl. 4, fig. 7

Pedinocyclus larvalis (Bukry & Bramlette, 1969)
Loeblich & Tappan, 1973
Pl. 3, figs 18, 25
6.2 Murolith Coccoliths
Order ZYGODISCALES Young & Bown, 1997
Family HELICOSPHAERACEAE Black, 1971
Helicosphaera bramlettei (Müller, 1970)
Jafar & Martini, 1975
Pl. 3, fig. 27
Helicosphaera clarissima Bown, 2005
Pl. 3, fig. 32
Helicosphaera compacta Bramlette & Wilcoxon, 1967
Pl. 3, fig. 31

73

Pontosphaera exilis (Bramlette & Sullivan, 1961)
Romein, 1979
Pl. 3, figs 35–37
Pontosphaera formosa (Bukry & Bramlette, 1969)
Romein, 1979
Pl. 4, fig. 5
Remarks: Our forms were smaller than the originallydescribed size of 14–17 µm (Romein, 1979).
Pontosphaera latoculata (Bukry & Percival, 1971)
Perch-Nielsen, 1984
Pl. 4, figs 8–11

Helicosphaera euphratis Haq, 1966
Pl. 3, fig. 26

Remarks: This species exhibited a wide variation in rim
thickness. It also had a single cycle of perforations aroundthe rim and an open central-area that varied in width.

Helicosphaera lophota (Bramlette & Sullivan, 1961)
Locker, 1973
Pl. 3, figs 33, 34

Pontosphaera multipora (Kamptner, 1948 ex Deflandre
in Deflandre & Fert, 1954) Roth, 1970
Pl. 3, figs 38–40

Helicosphaera reticulata Bramlette & Wilcoxon, 1967
Pl. 3, figs 29, 30

Pontosphaera pectinata (Bramlette & Sullivan, 1961)
Sherwood, 1974
Pl. 4, fig. 6

Helicosphaera wilcoxonii (Gartner, 1971)
Jafar & Martini, 1975
Pl. 3, fig. 28
Family PONTOSPHAERACEAE Lemmermann, 1908
Pontosphaera alta Roth, 1970
Pl. 3, figs 44–49
Pontosphaera distincta (Bramlette & Sullivan, 1961)
Roth & Thierstein, 1972
Pl. 3, figs 41, 42

Pontosphaera plana (Bramlette & Sullivan, 1961)
Haq, 1971
Pl. 4, figs 12–14
Pontosphaera obliquipons (Deflandre in Deflandre &Fert, 1954) Romein, 1979
Pl. 3, fig. 43
Scyphosphaera columella Stradner, 1969
Pl. 4, fig. 15

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Jones, Dunkley Jones

Plate 6

66A-51 Triquet. carinatus 32B-120

48A-54

60A-6082A-97 T. carinatus

49A-25

81A-46

73A-91

30A-53D. barbadiensis

55A-53 D. barbadiensis

D. saipanensis

Spheno. conicus 31A-40

48A-54

S. conicus

31A-40 S. moriformis

31A-40 S. radians

82A-97

S. radians

66A-51 S. pseudoradians

63A-23 S. obtusus

66A-51

S. obtusus

66A-51

79A-42 S. predistentus

S. predistentus

34B-124 S. tribulosus

34B-124

36A-4330A-53

34A-39S. akropodus

31A-40

31A-4038A-44Eocene–Oligocene nannofossils from Java

Scyphosphaera expansa Bukry & Percival, 1971
Pl. 4, figs 16, 17

Blackites stilus Bown, 2005
Pl. 4, figs 26, 27

Family ZYGODISCACEAE Hay & Mohler, 1967

Blackites subtilis? Bown & Newsam, 2017
Pl. 4, figs 35, 36

Neochiastozygus tenansa (Deflandre in Deflandre & Fert,
1954) Self-Trail, 2011
Pl. 5, figs 8–12
Family RHABDOSPHAERACEAE Haeckel, 1894
Blackites amplus Roth & Hay in Hay et al., 1967
Pl. 4, fig. 18
Blackites cf. B. globosus Bown, 2005
Pl. 4, figs 19, 20
Remarks: Small, squat and bulbous Blackites, with noobserved basal coccolith. These were likely broken specimens, with missing or very short, hollow spines. No ornamentation was seen across the sphere.
Blackites culter? Dunkley Jones et al., 2009
Pl. 4, fig. 21
Remarks: Only one specimen was recorded, and the species was questionable due to the specimen having a slimmer spine and a missing basal coccolith.
Blackites gladius? (Locker, 1967) Varol, 1989
Pl. 4, fig. 25
Remarks: A single, broken specimen was recorded, hence
the species identification is questionable.
Blackites inversus (Bukry & Bramlette, 1969)
Bown & Newsam, 2017
Pl. 4, figs 33, 34
Blackites spiculiformis Bown & Dunkley Jones, 2006
Pl. 4, figs 22, 23
Blackites spinosus (Deflandre & Fert, 1954)
Hay & Towe, 1962
Pl. 4, figs 29–32

75

Remarks: The identification of this specimen was questionable because it appears to taper at both ends; according
to the description in Bown & Newsam (2017), this species
does not taper at the ends. However, the tapering may be
due to the oblique angle causing a distorted view.
Blackites tenuis (Bramlette & Sullivan, 1961)
Sherwood, 1974
Pl. 4, fig. 28
Blackites tortilis Bown & Dunkley Jones, 2006
Pl. 4, fig. 24
Order SYRACOSPHAERALES Hay, 1977 emend.
Young et al., 2003
Family CALCIOSOLENIACEAE Kamptner, 1927
Calciosolenia alternans Bown & Dunkley Jones, 2006
Pl. 4, figs 37, 38
Family SYRACOSPHAERACEAE Lemmermann, 1908
Syracosphaera tanzanensis Bown, 2005
Pl. 4, figs 39, 40
6.3 Holococcoliths
Family CALYPTROSPHAERACEAE Boudreaux &Hay, 1967
Holodiscolithus minolettii Bown, 2005
Pl. 5, figs 5–7
Orthozygus aureus (Stradner, 1962)
Bramlette & Wilcoxon, 1967
Pl. 5, figs 13–16
Lanternithus minutus Stradner, 1962
Pl. 5, figs 1–4

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Jones, Dunkley Jones

Zygrhablithus bijugatus subsp. bijugatus(Deflandre in Deflandre & Fert, 1954) Deflandre, 1959
Pl. 5, figs 19–24
Clathrolithus ellipticus Deflandre in Deflandre & Fert,
1954
Pl. 5, figs 17, 18

very good, making species identification problematic.
Discoaster barbadiensis Tan Sin Hok, 1927
Pl. 6, figs 2, 3, 6
Discoaster distinctus Martini, 1958
Pl. 5, figs 37, 38, 41

6.4 Extant nannoliths
Order BRAARUDOSPHAERALES Aubry, 2013
Family BRAARUDOSPHAERACEAE Deflandre, 1947

Discoaster nodifer (Bramlette & Riedel, 1954)
Bukry, 1973
Pl. 5, figs 39, 40

Braarudosphaera bigelowii (Gran & Braarud, 1935)
Deflandre, 1947
Pl. 5, figs 25, 26

Discoaster saipanensis Bramlette & Riedel, 1954
Pl. 6, fig. 1

6.5 Extinct Nannoliths
Micrantholithus astrum? Bown, 2005
Pl. 5, fig. 27
Pemma basquense (Martini, 1959) Báldi-Beke, 1971
Pl. 5, figs 28, 29
Pemma papillatum Martini, 1959
Pl. 5, figs 30–32
Pemma triquetra Bown & Dunkley Jones, 2006
Pl. 5, figs 33, 34
Unknown nannolith
Pl. 5, figs 35, 36
Description: A form resembling a pinwheel, with five visible rays, although we suspected there were six rays in total, inferring that this nannolith possesses three pairs of triangular, overlapping segments. One segment in each pairgoes extinct when rotated to 45˚, revealing the segment
division. At 0˚, all the segments are bright. A small, circular central node is present, but has no outstanding features.
Occurrence: CNO3 (NP23).
Order DISCOASTERALES Hay, 1977 emend.
Bown, 2010
Family DISCOASTERACEAE Tan Sin Hok, 1927
Remarks: The overall preservation of this genus was not

Discoaster septemradiatus? (Klumpp, 1953)
Martini, 1958
Pl. 5, fig. 42
Remarks: The rays appear to curve proximally. There wasa possible underlying disc.
Discoaster tanii Bramlette & Riedel, 1954
Pl. 5, fig. 45
Discoaster tanii subsp. ornatus Bramlette & Wilcoxon,
1967
Pl. 5, figs 43, 44
Family SPHENOLITHACEAE Deflandre, 1952
Sphenolithus moriformis group
Pl. 6, figs 9–18
Sphenolithus conicus Bukry, 1971
Pl. 6, figs 9–16
Remarks: Small forms of this species were first documented in Upper Eocene sample NKK/1-54A (72.44mbgl) in CNE19 (NP19/20), with larger forms appearing
above, in the Lower Oligocene.
Sphenolithus moriformis (Brönnimann & Stradner, 1960)
Bramlette & Wilcoxon, 1967
Pl. 6, figs 17, 18

Eocene–Oligocene nannofossils from Java

Sphenolithus predistentus group
Pl. 6, figs 25–44
Sphenolithus akropodus de Kaenel & Villa, 1996
Pl. 6, figs 39–44
Remarks: The base of common S. akropodus was very
close to the base of the Oligocene in CNO1 (NP21).
Sphenolithus obtusus Bukry, 1971
Pl. 6, figs 25–30
Sphenolithus predistentus Bramlette & Wilcoxon, 1967
Pl. 6, figs 31–34
Remarks: A great variation in the shape of the spine andin the size were observed. The specimens ranged fromsmall to large, with spines that diverged distally.
Sphenolithus tribulosus Roth, 1970
Pl. 6, figs 35–38
Sphenolithus radians group
Pl. 6, figs 19–24
Sphenolithus radians Deflandre in Grassé, 1952
Pl. 6, figs 19–22
Sphenolithus pseudoradians Bramlette & Wilcoxon, 1967
Pl. 6, figs 23, 24
Nannoliths incertae sedis
Triquetrorhabdulus carinatus Martini, 1965
Pl. 6, figs 4, 5, 7, 8
Remarks: Occurred sporadically in both the Upper Eocene and Lower Oligocene sediments.
Acknowledgements
This project was funded by the CENTA Doctoral Training Pro-77

material. We also thank Jean-Self Trail and an anonymous re-viewer for their constructive comments and remarks. Nannofos-

sil occurrence data is available online (at figshare: https://doi.
org/10.6084/m9.figshare.12488783.v1).

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